Spie Press Book

Digital micro-optics is a particular field within the more general field of optical engineering, particular in the way such optics are designed (seldom through ray tracing) and how they are fabricated (often at the wafer scale). This book, written by Google engineer Bernard Kress, reviews the broad range of micro-optics used today in industry and research (refractives, GRIN, hybrid, diffractives, holographic, nano-optics). It provides quick access to optimal design and modeling techniques, both analytic and numeric. This book also reviews the various fabrication techniques used to produce micro-optics, as well as the requirements to bridge the gap between design and fabrication. The optical engineer interested in quick but concise answers to questions ranging from the design and modeling to the fabrication and mass replication of micro-optics will particularly enjoy this book.

Preface

The term "digital micro-optics" was introduced in the early 1990s to refer to a specific variety of micro-optics. It is now widely accepted by industry and academia. Digital micro-optics can be related to their counterparts in the electronics realm - "digital electronics," or "integrated electronics" (ICs) - in various ways, from design to modeling, from prototyping to mass fabrication, and eventually system integration. Historically, the term "digital" in digital electronics refers to three aspects:

their digital functionality (binary logic),

the way they are designed via a digital computer, and

the way they are fabricated (through sets of digital or binary masks).

In digital micro-optics, the term primarily refers to how such optics are designed and fabricated, similar to digital electronics, through specific electronic-design-automation (EDA) software packages and sets of digital masks. Traditional macro-optics, such as telescopes, microscopes, and other imaging optics, have been designed without complex design software tools. Digital optics, especially wafer-scale micro-optics, cannot be designed without specific software and tools. Digital layouts for wafer-level fabrication of micro-optics are also often generated by algorithms similar to the ones used in conventional EDA tools (Cadence, Synopsys, Mentor-Graphics, etc.). Because there is often no analytical solution to the micro-optics design problem, complex iterative optimization algorithms may be required to find an adequate solution.

Unlike digital electronics, digital micro-optics can implement either digital or analog functionality, or a combination thereof. A typical digital function may be a fan-out beam splitter, and an analog function may be an imaging task. A hybrid may result in a complex multi-focus imaging lens, a function impossible to implement in traditional analog macro-optics.